<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<script>
    "use strict";
    let nums = [1,2,323,31,9,-1];
    nums.forEach(function (value) {
        console.log(value)
    });
    for (let index in nums) {
        console.log(index + " : " + nums[index]);
    }
</script>

</body>
</html>